Conventionally, a shoe sewing machine comprises a rotating shuttle disposed within a head of a rocking arm which is located under the stitching device of the shoe sewing machine or the stitching device and the shuttle are disposed relative to each other in an up-and-down arrangement so that the up-and-down movement of the stitching device and the rotation of the shuttle are both moved in a uniform speed. The disadvantage of disposing the shuttle in the head of the rocking arm is that the shuttle has to move into the shoe to be sewn along with the head of the rocking arm to hook and pull out the thread. As a consequence, the size of the shuttle is thus subject to constraints. If the shuttle is large, then the movement of the shuttle into the shoe is difficult and thus affecting the stitching operation. If the shuttle is small, the spool on which the thread is wound has to be reduced in size and thus the thread that is wound on the spool has to be thinner or the overall length thereof wound on the spool is reduced. This leads to a disadvantage in that the spool has to be changed frequently during shoe sewing operation.
It is therefore desirable to provide a shoe sewing machine to overcome the deficiency associated with the disposition of the shuttle within the head of the rocking arm by disposing the shuttle adjacent the stitching device to provide the convenience of easy to change spool and the use of a large size spool which allows more thread to be wound on the spool and requires no frequent change of the spool. It is also desirable to provide a non-uniform speed sewing or stitching operation to improve the deficiency associated with the uniform speed sewing operation provided by the conventional shoe sewing machines.